3.1.2 - Memory

Note: The MSM was created by Atkinson and Shiffrin in 1968.

Sensory register

• Duration - 1/4 to 1/2 of a second
• Capacity - very large
• Encoding - sense-specific (e.g. iconic store for visuals, echoic for audio, etc.)

Short-term memory

• Duration - 18 to 30 seconds
• Capacity - 7 +/- 2 items
• Encoding - mainly acoustic

Long-term memory

• Duration - unlimited
• Capacity - unlimited
• Encoding - mainly semantic (information with similar meanings grouped together)

• Information is detected by the sense organs
• Information enters the sensory register / sensory memory
• If the information is paid attention to, it passes into the short-term memory
• If the information is ignored, it decays and is forgotten
• In the short-term memory, information must undergo maintenance rehearsal else it is lost through displacement or decay
• Only when the information is the short-term memory is elaboratively rehearsed will it be transferred to the long-term memory
• Information does not have to be rehearsed to remain in the long-term memory
• Information stored in the long-term memory can be retrieved

Positives

• It is supported by case studies of amnesia patients such as HM and Clive Wearing. HM retained some old memories but his ability to use the short-term memory store was impaired. Clive Wearing could not transfer new information from his short-term memory to his long-term memory. These support the idea that there are separate stores within our memory.
• Murdock's 'Primacy and Recency Effect' research supports the MSM. He found that, when given a list of words to remember, immediate recall of the first and last few words was best. He argued that this was because the first words had been rehearsed and therefore transferred into long-term memory (primacy effect), and the last words were given recently enough that they were still in the short-term memory (recency effect).

Negatives

• There is an overemphasis on the role of rehearsal in the MSM. It does not take other factors into consideration. For example, memories from childhood are not rehearsed, but they must be in the long-term memory because they happened many years ago and are still remembered.
• The MSM is reductionist, or oversimplified. It is unlikely that all types of memory are stored in one long-term memory store. In fact, Tulving identified three types of long term memory - procedural, episodic and semantic.
• Although case studies can provide lots of detailed information, the information from them cannot be generalised to the wider population. Another issue of using case studies to study memory is that it cannot really be seen where the issue in the brain lies until the patient dies, and only then if they give consent. This can make the process incredibly time-consuming.

Note: These types of long term memory were identified by Tulving.

Episodic memory

• Declarative (consciously recalled) memories
• Linked to personal experiences
• Consists of three parts: details of the event; emotions you felt at the time, and the context in which it happened

Semantic memory

• Declarative memory
• Linked to facts, such as capital cities or appropriate behaviours
• Usually start as episodic but become semantic as the personal association fades

Procedural memory

• Linked to skill-based information
• Become automatic after repetition, which is what allows us to multi-task

Positives

• Supporting research from brain scanning technology, which has discovered that different parts of the brain are active when different types of LTM are being used. Episodic memories are associated with the hippocampus, the temporal lobe and the frontal lobe. Semantic memories use the temporal lobe, and procedural memories use the cerebellum.
• Supporting research from Corkin using Milner's case study of HM (mentioned in the MSM evaluation). They found that HM was able to trace a shape using its mirror image and retain the skill, but he had no memory of learning to do this afterwards. This proves there are different LTM stores; his procedural memory was intact but his episodic and semantic memories were not.
• Supporting case study of Clive Wearing (also mentioned in MSM evaluation). He retained his procedural memory of playing the piano well, but was unable to form new episodic or semantic memories. This also shows that there must be different stores within the long-term memory.

Negatives

• A weakness of using case studies of amnesiacs is that, while lots of detailed information can be gathered, it is difficult to identify the damaged part of the brain until the patient dies, and only then if the consent to being tested on after death. This makes research into LTM more complex and time-consuming.
• Cohen and Squire argue that there are two, not three, long term memory stores. These are declarative memory, which involves conscious recall, and non-declarative memory, which involves unconscious recall.

Note: The WMM was created by Baddeley and Hitch.

Central executive

• Monitors incoming information and decides what information to pay attention to
• Allocates information to one of the slave systems

Visuospatial sketchpad (VSS)

• Temporary cache storing 3/4 units of information linked to visual and spatial information

Phonological loop

• Consists of the phonological store (holds words heard for 1-2 seconds) and the articulatory control system (rehearses sounds/words in a loop to keep them in the store)

Episodic buffer

• Integrates information from other slave stores
• Sends completed, multimodal memory to LTM

Positives

• The WMM is supported by findings from dual task studies. It is easier to multi-task when the tasks use different processing systems. When both tasks are using the same system, recall is worse and will have more errors.
• The case study of KF supports the WMM. KF suffered brain damage from a motorcycle crash. He could recall visual information, but could not recall verbal information. This shows that there are separate stores for different types of information within the STM. Case studies also provide rich, detailed information about a particular patient.

Negatives

• There is little information on the central executive, how it works and if it even exists; as it is a key feature of the WMM, this is a large weakness of the model as a whole.
• Case studies lack population validity because each patient's condition is unique. This means findings of case studies cannot be generalised to the wider population.
• The WMM may be reductionist. Lieberman says the VSS implies that all spatial information was once visual. However, blind people have excellent spatial awareness but never had visual input.

Interference theory suggests that forgetting is due to information in the LTM becoming confused with or disrupted by other information, leading to inaccurate recall. This is more likely to occur if both sets of information are similar.

There are two types of interference: proactive and retroactive.

• Proactive: old information interferes with an attempt to recall new information
• Retroactive: new information interferes with an attempt to recall old information

Positives

• Supporting research from Baddeley and Hitch. They asked rugby players to remember as many teams they had played against as possible. They found that forgetting was more due to the amount of games played rather than the time that had passed between games. This proves that interference leads to forgetting.

Negatives

• Much of the supporting research for intereference theory comes from lab studies. These lack ecological validity because they do not reflect the way we remember or forget things in real life, as in a lab study, the time between learning and recall is much shorter than it would be in real life.
• Intereference theory only explains forgetting when the information is similar. There are many types of recall not explained by this theory.

Note: This is also known as retrieval failure, and was created by Tulving.

Tulving's Encoding Specificity Principle states that the greater the similarity between the encoding event and the retrieval event, the greater the likelihood of recalling the memory.

Cue-dependent forgetting occurs when a person cannot retrieve information in their long-term memory. This is because certain cues were stored with the memory, and now these cues are absent, so the memory cannot be accessed.

There are two main types of cue-dependent forgetting:

• State dependent forgetting - this occurs when certain internal bodily cues that were present at the time of learning are now absent
• Context dependent forgetting - this occurs when certain external environmental cues that were present at the time of learning are now absent

Positives

• Supporting research for context dependent forgetting from Godden and Baddeley. Scuba divers asked to learn a list of words, either on land or underwater. They then had to recall these words, again either on land or underwater. They found that recall was best when the learning and recall environment was the same.
• Supporting research for state dependent forgetting from Goodwin et al. Male volunteers asked to learn a list of words when either drunk or sober. They were asked to recall the words 24 hours later when they were either drunk or sober. They found that recall was highest when they were in the same psychological and physical state as learning.
• There could be real life applications. Cues can help eyewitnesses recall events better when they are testifying. People with dementia can create 'memory boxes' filled with items that had some significance in their life. These cues can help them remember parts of their lives.

Negatives

• Most of the research supporting retrieval failure theory is highly controlled. This means they can lack ecological validity as they do not reflect real life, thus decreasing the value of retrieval failure as an explanation.
• Goodwin's study (see previous card) only used male volunteers, so it is androcentric. This meand it cannot be generalised to females, so it is not representative of wider society.

Misleading information: leading questions

• Misleading information is information that suggests a desired response
• Leading questions direct the eyewitness in a certain direction so they will answer in a way that the interwiewer wants them to

Misleading information: post-event discussion

• Post-event discussion can lead to information being added to a person's memory of an event after the event has occured

Anxiety

• Anxiety can decrease accuracy of EWT because of distraction and emotional and physical arousal
• Anxiety can also increase accuracy because of increased alertness

Note: Experiment carried out by Loftus and Palmer in 1974.

• Aim - To assess the effects of misleading information.
• Sample - Exp. 1 used 45 students, Exp. 2 used 150 participants.
• Procedure - Exp. 1 - Participants were split into groups and watched a video of a car crash. They were then interviewed and asked the critical question, 'How fast were the cars going when they ... each other?' The gap was filled by one of three verbs - 'contacted', 'hit', 'bumped', 'smashed' and 'collided'. Exp. 2 -  They split participants into three groups (one control) and used two of the previous conditions, 'hit' and 'smashed'. They followed up with participants a week later and asked them a new critical question, 'Did you see any broken glass?' There was no broken glass. 
• Findings - Exp. 1 - Highest mean estimate was for smashed (40.8 mph). Lowest mean estimate was for contacted (31.8). Exp. 2 - 16/50 in the smashed condition said yes, compared to 7/50 in the hit condition.
• Conclusion - Misleading information distorts memory and accuracy of EWT.

Strengths

• There has been further research to support the idea that post-event information affects EWT. LaRooy (2005) found that, when interviewing children, the more times they were interviewed, the higher the chance that something said by the interviewer will be incorporated into their recall.

Limitations

• Loftus and Palmer's study lacks population validity as the sample was limited.
• Loftus and Palmer's study lacks ecological validity as it was conducted in an artificial laboratory setting that is not reflective of a real-life situation. It is likely that the level of anxiety when watching the clip would be less than seeing a car crash in real life. They may also have paid closer attention because they were told to watch the clip.

Note: This experiment was conducted by Gabbert et al in 2003.

• Aim - To see whether or not EWT would be affected by post event discussion.
• Sample - 60 university students and 60 older adults.
• Procedure - Participants took part either individually or in pairs. They all watched a video of a girl stealing a wallet. The pairs were led to believe they would watch the same video, when they actually watched the event from different perspectives and only one of them actually saw the crime being committed. The pairs then discussed the event. All participants completed a questionnaire about what they had seen.
• Findings - 71% of eyewitnesses in the pairs condition recalled information they had not seen but had been mentioned in discussion, compared to 0% in the individual condition. 60% of participants in the pairs condition claimed the girl was guilty without having seen her steal the wallet. The findings were similar in all ages.
• Conclusion - When co-witnesses of a crime discuss it with each other, their EWT many become contaminated. This is because they combine (mis)information from other witnesses with their own memories.

Strengths

• Real-life application. Police now know to separate witnesses as soon as possible and warn them of the dangers of discussing events with others. If there are inaccuracies in testimnoies, the case may not result in prosecution, creating economic implications as time and money is wasted on trying to get a conviction. It could even save an innocent person from conviction.
• Supporting research from Eakin et al (2003). Showed participants slides of a man stealing money and a calculator. Eyewitness testimony was impaired by misleading PED, even when the particiants were warned about misleading information and told to disregard it.

Limitations

• Gabbert et al's study is not clear on whether the distortions in EWT reflect problems with memory or reflect social pressure (memory conformity).
• Bodner et al challenges Eakin's study (above). They found that the effect of PED can be reduced if eyewitnesses are informed of its detrimental effects. Recall was more accurate when participants were told to disregard second-hand information, and recall only what they had seen themselves.

Note: This experiment was conducted by Johnson and Scott in 1976.

• Aim - To discover if anxiety during a witnessed incident affects the accuracy of later identification.
  
• Sample - Two groups of participants.
  
• Procedure - Group One were exposed to a situation where they heard a calm conversation and saw a man exit the lab with greasy hands, holding a pen. Group Two overheard a heated exhange in the lab and heard breaking glass. A man later exited the lab holding a bloody knife. Both groups were then given 50 photos and asked to identify the person that left the room.
• Findings - Group One correctly identified the man 49% of the time. Group Two correctly identified him 33% of the time.
• Conclusion - The presence of a weapon reduces the accuracy of EWT, as the weapon distracts attention from the appearance of the perpetrator. It causes fear or anxiety and heightens accuracy of recall of central details, but reduces the memory of peripheral details. Known as weapon focus effect.
  

Limitations:

• Experiment is low in ecological validity. The procedures were artificial, so they lack mundane realism.
• Ethical issues. The participants were deceieved; they believed they were waiting to take part in the experiment while they heard these conversations. This means they would have felt a higher level of anxiety, so they were not preotected from harm.
• Contradictory evidence from Yeoville and Cutshall. They investigated the effect of anxiety in a real life shooting. 21 witnesses were originally interviewed by investigating police and 13 witnesses took part in their follow-up research 4-5 months later. Yuille and Cutshall found that the witnesses were still accurate in their eyewitness accounts. All of the major details of their reports remained the same and only minor details changed. This shows that in real life cases of extreme anxiety, the accuracy of eyewitness testimony is not affected.

The cognitive interview is a police interviewing technique. The steps of the CI are as follows:

• Recall everything. Interviewer asks eyewitness to recall everything, even details they believe are trivial.
• Reinstate the context. The interviewer tries to recreate the emotional and physical context of the event so that the emotional and environmental cues present at the time of the event are there, helping to make memories accessible.
• Recall in a different order. The interviewer moves backwards and forwards in time, for example asking the eyewitness to start at the end and move backwards. This makes it more difficult to use existing schemas to confabulate information.
• Recall from a different perspective. This involves the eyewitness recalling the event as someone else saw it, for examply the perpetrator. This is another attempt to prevent them from using existing schemas to confabulate information.

There are two variations on the standard version described below: the enhanced cognitive interview (focused on building a rapport with the interviewer and the witness controlling the flow of information) and the modified cognitive interview (adapted for children and people with learning disabilities).

Strengths:

• Real world application. The CI could replace the standard interview in order to try and prevent leading questions and inaccuracies in statements. This is important as, in court, a jury can be swayed if the witnesses are discredited.
• Supporting research from Geiselman et al. They found that students recalled considerably more in a cognitive interview than a standard interview. However, error rates were similar. Shows that the CI does increase the amount of correct information recalled.

Limitations:

• Kohnken et al said that police need to treat information gained by CI with caution. While there was an 81% increase in correct information, there was also a 61% increase in incorrect recall. Questions the quality rather than the quantity of information given by eyewitnesses.
• Kebbell and Wagstaff found that the CI is incredibly time-consuming and therefore expensive to carry out. It is also costly to provide the necessary training to police officers. Many police stations cannot afford this so the CI has not been widely adopted.